The champion Sydney trio has never all had runners at the same July Carnival.

And adding to the list of big guns attending, Patinack Farm, mining magnate Nathan Tinkler's massive thoroughbred operation headed by lead trainer John Thompson, is also targeting the carnival.

Throw in the likes of multiple Group One trainers like John O'Shea, Clarry Conners and Melbourne-based Kiwi Mike Moroney and the signs are there for one of the most hotly contested carnivals in recent years.

Tomorrow's opening fixture gave a portent to what can be expected in terms of numbers, with more than 280 horses from across New South Wales and interstate nominated.

"I'd certainly like to think the interest shown Thursday is evidence of what's to come," Clarence River Jockey Club chief executive Bradley de Martino Rosaroll said.

"It's shaping as a great carnival.

"There's a lot of interest out there. The increased prizemoney this year appears to be having an effect.

"We're hoping for high-class nominations for the Ramornie and Grafton Cup, taking them to a new level."

Snowden, who heads Sheikh Mohammed's Australian Darley stable, returns to Grafton trying to win his third $150,000 WHK Ramornie, after Pinwheel and Jerezana won the past two editions.

Snowden is third on the Sydney trainers' premiership with 58 wins, trailing Waterhouse (82) and leader Waller, who has 95.5 wins.

Darley-owned pair Parthian and Skytrain will be nominated for the Ramornie, Peck for the $150,000 Maclean Bowling Club Grafton Cup and The Owl for the $50,000 Tursa Employment & Training Grafton Guineas.

"I'll also be bringing up a couple of maidens," Snowden said. "I'm looking forward to coming."

Waller will nominate Disciple for the Grafton Guineas and Waterhouse has two-year-old Rampaging ready to "bowl em' over" in the $40,000 NBN Inglis Bonus.

The two-year-old is part-owned by New South Wales and Australian cricketer Doug Bollinger.

Nash Rawiller, who returns from holiday this week, will be offered the ride.

Moroney has Shenzou Steeds chasing a unique treble, the Ipswich, Caloundra and Grafton cups, while Thompson is considering Sharmadashing and Saint Encosta for the Grafton Cup.

O'Shea will nominate last-start Newcastle winner Art Thou Ready for the Guineas and Conners has Turnley, part-owned by former trainer and regular Grafton visitor Tommy Sewell, for the Inglis 2YO.